Figure 7.
Overexpression of Numb promotes branching and lengthening of sensory axons. (A–D) Depiction of representative images of neurons expressing EGFP (A) or EGFP-numb (B) grown in NGF or in the presence of NT3 (C,D). Neurons were infected with HSV expressing EGFP or EGFP-numb, allowed to grow for 48 h, and processed for image analyses. (E) Quantification of changes in axon branch points, maximal axon length, and total axon length in sensory neurons expressing EGFP, EGFP-numb, or EYFP-NumbΔ557–593. Expression of EGFP-numb, but not EYFP-NumbΔ557–593, drastically increased the number of collateral branches (left), maximal axon length (middle), and total axon length (right). (F) Expression of EGFP-numb also had a similar effects on the axon branching and length in NT3-responsive neurons. Bars: A–D, 100 μm. Paired Student's t-tests were used to for statistical analyses. *p < 0.01; ns indicates not significant.